1. Field of Invention
The invention relates to a method and apparatus for closing a hole or puncture which has been made in a blood vessel.
2. Description of the Related Art
In several surgical procedures it is necessary to puncture a blood vessel in order to insert a tube into the blood vessel. Typically, the tube is a sheath in the 8-11 French size, and, consequently the hole following sheath removal, can be quite significant. Frequently, after conventional diagnostic arteriography, whether for the peripheral circulation or for the coronary circulation, excessive bleeding occurs on removal of the catheter or femoral artery sheath. Furthermore, the hematomas can be more significant, and the bleeding complications greater, in those post-interventional procedures in both cardiology and radiology. People who have hypertension, obesity, bleeding disorders or post thrombolitic therapy and people under medications which inhibit clotting, are all high risk patients for excessive bleeding to occur following removal of the sheath. The present medical practice is to first attempt to close the puncture by use of mechanical compression or a collagen plug. If these techniques do not promptly cause a clot to form closing the puncture, significant blood loss can occur. In these instances, microvascular surgery may be an option.
The refinements of technique in microvascular surgery have developed in two directions. The first approach is the use of microsuture techniques. These surgical techniques have advanced with the aid of the development of operating microscopes, microsutures and miscroinstruments. They produce very accurate anastomosis and yield good results. However, the techniques have not been widely used because they not only have the disadvantage of being time consuming, but they also have the disadvantage of requiring an extremely high degree of technical skill. The presence of suture material in the interior of a blood vessel can also present a nidus for clot formation.
The second approach has been in the direction of various mechanical devices or glues which attempt to circumvent the exacting skill and prolonged time required for the suturing techniques. The glues have generally been unsuccessful because of complications involving tissue toxicity and reaction. Stapling techniques have been cumbersome and have been difficult to use on vessels under 2 mm. in size. Other devices have included various tubes, flanges and rings. These devices are not suitable for rapid placement over a puncture. Moreover, excessive bleeding can still occur. Therefore, there is a need for a method and apparatus for closing blood vessel punctures which is particularly useful for those patients who are at high risk of bleeding from such punctures. Preferably the closure should be capable of placement over the puncture by insertion through the sheath for which the puncture was made.
In my U.S. Pat. application Ser. No. 07/843,384, now U.S. Pat. No. 5,234,448, I disclose a stent for sealing severed blood vessels. That stent includes a flexible sheet having micromechanical barbs which wraps around the outer surface or inner surface of the severed blood vessel. Although this closure can be wrapped around a blood vessel to cover a puncture, significant blood loss could occur while that closure is being fitted in place. Furthermore, this type of closure encircles the entire blood vessel rather than covering only the puncture site and adjacent area necessary to accomplish closure.
It would be preferable for the closure to be placed over the puncture prior to or immediately after removal of the sheath thereby minimizing blood loss through the puncture.